‘Last year was bad enough, this is a disaster,’ says one expert as Australia Research Council finds fresh damage across 8,000km

Back-to-back severe bleaching events have affected two-thirds of Australia’s Great Barrier Reef, new aerial surveys have found.
The findings have caused alarm among scientists, who say the
proximity of the 2016 and 2017 bleaching events is unprecedented for the
reef, and will give damaged coral little chance to recover.

Mass bleaching – a phenomenon caused by global warming-induced rises
to sea surface temperatures – has occurred on the reef four times in
recorded history.
Prof Terry Hughes, who led the surveys, said the length of time coral
needed to recover – about 10 years for fast-growing types – raised
serious concerns about the increasing frequency of mass bleaching
events.
“The significance of bleaching this year is that it’s back to back,
so there’s been zero time for recovery,” Hughes told the Guardian.
“It’s
too early yet to tell what the full death toll will be from this year’s
bleaching, but clearly it will extend 500km south of last year’s
bleaching.”

Aerial surveys of the world’s largest living structure, scoring
bleaching at 800 individual coral reefs across 8,000km.

But Hughes said its slow movement across the reef was likely to have
caused destruction to coral along a path up to 100km wide.
“It added to
the woes of the bleaching. It came too late to stop the bleaching, and
it came to the wrong place,” he said.
The University of Technology Sydney’s lead reef researcher, marine
biologist David Suggett, said that to properly recover, affected reefs
needed to be connected to those left untouched by bleaching.
He said Hughes’ survey results showed such connectivity was in
jeopardy.
“It’s that connection ultimately that will drive the rate and
extent of recovery,” Suggett said. “So if bleaching events are moving
around the [Great Barrier Reef] system on an annual basis, it does
really undermine any potential resilience through connectivity between
neighbouring reefs.”
Some reef scientists are now becoming despondent.
Water quality
expert, Jon Brodie, told the Guardian the reef was now in a “terminal
stage”.
Brodie has devoted much of his life to improving water quality on the reef, one of a suite of measures used to stop bleaching.

ARC conducted an aerial and underwater survey of the reef which
concluded that two-thirds of it has been hit by mass coral bleaching for
second time in 12 months.

Photograph: Ed Roberts/ARC

He said measures to improve water quality, which were a central tenet
of the Australian government’s rescue effort, were failing.
“We’ve given up. It’s been my life managing water quality, we’ve
failed,” Brodie said.
“Even though we’ve spent a lot of money, we’ve had
no success.”
Brodie used strong language to describe the threats to the reef in
2017.
He said the compounding effect of back-to-back bleaching, Cyclone
Debbie, and run-off from nearby catchments should not be understated.
“Last year was bad enough, this year is a disaster year,” Brodie
said.
“The federal government is doing nothing really, and the current
programs, the water quality management is having very limited success.
It’s unsuccessful.”

Others remain optimistic, out of necessity.
Jon Day was a director of
the Great Barrier Reef Marine Park Authority for 16 years until retiring
in 2014.
Day, whose expertise lies in protected area planning and management,
said the federal government’s approach to protecting the reef was sorely
lacking.
He said it was taking too relaxed an approach to fishing,
run-off and pollution from farming, and the dumping of maintenance
dredge spoil.
The government was far short of the $8.2bn investment needed to meet water quality targets, he said, and Australia was on track to fail its short-term 2018 water quality targets, let alone achieve more ambitious long-term goals.
“You’ve got to be optimistic, I think we have to be,” Day said.
“But
every moment we waste, and every dollar we waste, isn’t helping the
issue. We’ve been denying it for so long, and now we’re starting to
accept it. But we’re spending insufficient amounts addressing the
problem.”

The latest surveys spell more bad news for the Great Barrier Reef. Following a record high water surface temperature and mass bleaching event in 2016, the Australian icon may be on track for a similar event this year.

Aerial and underwater footage from 2016 and 2017, shown in this video, shows the extent of the bleaching and die-off, which has already impacted large portions of the reef.

The Queensland
tourism industry raised questions about the reliability of the survey,
saying scientists had previously made exaggerated claims about mortality
rates and bleaching.

“There is no doubt that we have had a significant bleaching event off
Cairns this time around,” said Col McKenzie, of the Association of
Marine Park Tourism Operators.
“The far north probably did a little bit better, Port Douglas to
Townsille has seen some significant bleaching,” he said.
“Fortunately we
haven’t seen much mortality at this time, and fortunately the
temperatures have fallen.”
McKenzie said more money needed to be invested in water quality
measures, and criticised what he saw as a piecemeal and uncoordinated
approach to water quality projects up and down the coast.

Underwater video shows where bleaching has damaged the Great Barrier Reef